1. Field of the Invention
The present invention relates generally to synthesis of micro and nanoscale size particles for drug delivery, and particularly, to a method of preparing modified chitosan particles for oral insulin delivery.
2. Description of the Related Art
It is well known that insulin is essential for type 1 and advanced type 2 diabetics to maintain blood glucose levels. In 2015, 402 million people throughout the world suffered from diabetes. It is expected that the number of diabetics will increase to 592 million by 2035. Diabetics injected with insulin often suffer from pain, tenderness, local tissue necrosis, microbial contamination and nerve damage due to continuous injection. It was previously recommended that natural polymers at micro and nanoscale sizes are preferred for oral drug delivery due to non-toxicity and good biological and anti-microbial activity.
Chitosan (CS), as a natural polysaccharide, possesses valuable properties including biocompatibility, biodegradability and non-toxicity. As such, chitosan has been used as a natural polymer for insulin release. Obtaining monodisperse nanoparticles based on ionic gelation using sodium tripolyphosphate has been previously reported. Different types of polymeric chitosan nanoparticles have been tested in in vitro and in vivo studies in diabetic animal models. However, natural CS is water-insoluble at alkaline and neutral pH, a result of its amino group deprotonation, causing the impairment of its mucoadhesiveness at pH 7.4. Introduction of trimethyl groups onto the structure of CS has been shown to highly improve the water-solubility of CS due to the relatively easier protonation of the quaternary amine groups. It was also reported that pH-responsive nanoparticles consisting of CS and poly(g-glutamic acid) (PGA) for oral delivery of insulin showed a higher stability over a broader pH range from 2.0 to 7.2.
Thus, modified chitosan nanoparticles for delivering oral insulin for treating diabetes thereby solving the aforementioned problems is desired.